Bay Bridge rod troubles extend to base

Vulnerable steel in base can't be easily inspected

Updated 8:56 pm, Saturday, May 11, 2013

Caltrans spokesman Will Shuck holds a section of a steel bolt removed from the Bay Bridge's new eastern span for testing.

Caltrans spokesman Will Shuck holds a section of a steel bolt removed from the Bay Bridge's new eastern span for testing.

Photo: Max Whittaker/Prime, Special To The Chronicle

Image 2 of 5

Image 3 of 5

A section of bolt removed from the new Bay Bridge in after breaking during a Charpy V notch impact test at Caltrans TransLab in Sacramento, California, May 9, 2013. Caltrans is testing the so-called "2010 rods", following the failure of 32 three-inch steel rods that broke during construction. less

A section of bolt removed from the new Bay Bridge in after breaking during a Charpy V notch impact test at Caltrans TransLab in Sacramento, California, May 9, 2013. Caltrans is testing the so-called "2010 ... more

Photo: Max Whittaker/Prime, Special To The Chronicle

Image 4 of 5

A section of bolt removed from the Bay Bridge is milled in preparation for tensile and elongation testing at the Caltrans lab in Sacramento.

A section of bolt removed from the Bay Bridge is milled in preparation for tensile and elongation testing at the Caltrans lab in Sacramento.

Photo: Max Whittaker/Prime, Special To The Chronicle

Image 5 of 5

Section of bolt before and after breaking during tensile and elongation testing at Caltrans TransLab in Sacramento, California, May 9, 2013. Caltrans is testing the so-called "2010 rods", following the failure of 32 three-inch steel rods that broke during construction. less

Section of bolt before and after breaking during tensile and elongation testing at Caltrans TransLab in Sacramento, California, May 9, 2013. Caltrans is testing the so-called "2010 rods", following the failure ... more

Photo: Max Whittaker/Prime, Special To The Chronicle

Bay Bridge rod troubles extend to base

1 / 5

Back to Gallery

The base of the new Bay Bridge eastern span's signature tower is secured by more than 400 high-strength steel rods that were galvanized under conditions Caltrans barred as putting them at risk of cracking, The Chronicle has learned.

The tower is the dominant feature of the $6.4 billion eastern span, which is supposed to open over Labor Day weekend - a schedule that is now up in the air because of problems with how the tower rods and nearly 2,000 other steel fasteners were made.

The 525-foot-tall tower has been the central feature of the span since plans were drawn up in 1998. The landmark survived then-Gov. Arnold Schwarzenegger's efforts in 2004 to scrap it due to cost and replace it with a concrete causeway. In recent weeks the scaffolding has gradually disappeared from around the tower, revealing the structure silhouetted on the Golden State Warriors' uniforms.

Not visible are the 424 threaded rods - 24 feet long and 3 and 4 inches in diameter - that are among those Caltrans has belatedly realized are vulnerable to being invaded by hydrogen that could cause them to become brittle and crack.

Caltrans can sample many of the 2,306 problematic steel rods on the span in an effort to determine whether they will hold up. However, it cannot easily inspect, remove or replace those that sit at the base of the tower because the mammoth structure was lowered onto them in pieces.

"We are aware of the issue," Caltrans spokesman Will Shuck said of the tower rods. "These are going to get added scrutiny. We're going to make 100 percent sure they are safe."

In an earthquake, the rods would perform a vital task - countering the swaying forces on the tower. Caltrans officials say the rods are not being subjected to a high stress load, which they say reduces the risk they could crack.

Some outside experts, however, said the way the tower rods were manufactured makes them vulnerable to minor cracking that could suddenly worsen in an earthquake.

Problems in long run

"The problem is going to be that, over a long time, you start to see some cracks," said Russell Kane, an expert on metal embrittlement and corrosion who owns a consulting firm in Texas. In an earthquake, he said, "you are going to have some of those pre-existing cracks that are going to grow like crazy."

"If you have cracks in them, all bets are off," Kane said. "The thing could be swaying in the wind very quickly."

Like the other problematic steel rods on the eastern span, the ones at the base of the tower were made to an industry standard known as A354 BD. That denotes that the steel is of high strength and is allowed to be galvanized - a process in which the rods are dipped in molten zinc, intended to keep them from rusting.

But federal and state highway officials have long warned against galvanizing such high-strength steel and using it on bridges because of the possibility it will fail.

Galvanizing risk

Galvanizing can seal in hydrogen, which can cause cracking. It can also make it easier for hydrogen to invade the steel through flaws in the coating, by way of an electro-chemical reaction.

Caltrans banned such rods from bridges in 2000 because of the chance the steel could become brittle during the galvanizing process. The agency made an exception, however, for the A354 BD galvanized rods on the new Bay Bridge - after instructing manufacturers to remove a step in the galvanization process in which the metal is pickled in hydrochloric acid before being dipped in zinc. They hoped that would minimize the risk of hydrogen invasion.

"Generic specifications are for a run-of-the-mill bridge," Caltrans Director Malcolm Dougherty explained, "and this bridge is not run-of-the-mill."

In avoiding the acid baths, Caltrans was following the advice of the American Society for Testing and Materials, an industry standards group that establishes specifications.

Failed rods

Already, however, it's clear that Caltrans' precaution was far from foolproof: In March, 32 of the rods on a seismic-stability structure on the new eastern span snapped when they were tightened, even though they had not been subjected to hydrochloric acid.

Experts have speculated the destructive hydrogen could have come from rainwater that filled the rods' holes after they were installed on the bridge, although a committee of experts that Caltrans convened reported last week that unspecified problems during galvanization were the "likely" source of the contamination.

The rods at the base of the tower, however, were subjected to the acid baths, according to the company that supplied them in 2006 and 2007. Caltrans had specified that the rods should not get the acid treatment, but somehow those instructions never made it to the galvanizer.

Caltrans says it learned about the mistake during an audit it launched last month into the bridge rods after it became clear there had been problems in the manufacturing.

"We're going to get to the bottom of it," said Worth, whose agency oversees Caltrans' work on the bridge. "We want to figure out what happened and then understand what the solution might be."

Big danger

Joseph Nicoletti, a veteran seismic engineer who until recently served on a Bay Bridge advisory panel for Caltrans, said the potentially at-risk rods serve a vital purpose - to check the shear forces in a quake.

If they failed, he said, the tower could move horizontally. "That's something you don't want," he said.

Nicoletti speculated that the pitfalls of using galvanized high-strength steel were not fully understood by the bridge's designers or Caltrans.

"When you are doing a state-of-the-art job, you are playing with the state of the art in metallurgy and everything else," he said. "I'm not surprised something like this came up. Unfortunately, it came up at a bad time, and at quite a cost."

Records show the 424 tower rods were made by Vulcan Threaded Products in Alabama, which received the order through the contractor that built the tower, Kiewit-FCI-Manson joint venture, via two intermediary companies.

Although the bid order that Caltrans issued in 2003 shows the rods were supposed to be specially galvanized and not subjected to a hydrochloric acid bath, a Vulcan executive said those instructions never made it to the company.

"We manufactured a quality product. We manufactured to the specifications that they asked for," said Alan Logan, operations manager for Vulcan. "It appears that they full-court-pressed us to get this material to them."

Vulcan sent the rods to be galvanized by a Tennessee company, which pickled them in hydrochloric acid before dipping them in molten zinc.

No guarantees

Logan said there was no guarantee the rods at the base of the tower won't crack.

"The problem is that nobody can say that," he said. "You really don't know."

Caltrans officials say they are trying to assess the vulnerability of the tower's rods, but pointed out that they have already been inspected and have been performing satisfactorily. "We're just not ready to make a decision about them or any of the other rods until we have completed the metallurgical analysis that is under way," said Caltrans spokesman Shuck.

"If they need further study they're going to get it, because we're absolutely going to deliver a safe bridge."

But vouching for the rods will not be easy - removing one to be tested would be all but impossible. They are embedded in concrete that rests atop pilings driven deep into bedrock.

One approach would be to sample their characteristics and try to assess which among them might be the most vulnerable to cracking. "You ought to be able to point to the ones that will be most at risk, and those are the ones you would have to find a way to reinforce," corrosion expert Kane said.

The executive director of the transportation commission, Steve Heminger, was not aware of any unusual quality control issues with the rods from Vulcan.

Governor optimistic

"You have to examine what are the mechanical properties of those" rods, Heminger said. "Based on my own experience on this bridge, Caltrans quality control has been pretty rigorous," he said, adding that he is especially curious to see what might have gone wrong.

Ultimately, Heminger said, the decision on whether to open the bridge over Labor Day weekend is likely to be made by elected officials, including Gov. Jerry Brown.

Brown told reporters last week that it was too early to "pull our hair out" over the bridge problems and that he's optimistic everything will be OK.

Latest from the SFGATE homepage:

Click below for the top news from around the Bay Area and beyond. Sign up for our newsletters to be the first to learn about breaking news and more. Go to 'Sign In' and 'Manage Profile' at the top of the page.